Diodes Incorporated ZUMT918TA

Overview

ZUMT918TA from Diodes Incorporated is an NPN silicon planar RF transistor in SOT323 package, rated for V_CEO = 15 V, I_C = 100 mA, and f_T = 600 MHz, optimized for VHF/UHF amplifier and oscillator stages in portable communications equipment.

For engineers reviewing the ZUMT918TA datasheet, ZUMT918TA pinout, ZUMT918TA application, or ZUMT918TA equivalent, key selection criteria include its 600 MHz transition frequency, 15 dB common-emitter power gain at 200 MHz, low 6.0 dB noise figure at 60 MHz, and SOT323 thermal performance under pulsed RF drive conditions.

Technical Context

This device employs a planar epitaxial structure with gold-metallized emitter bonding to support stable high-frequency operation up to 600 MHz. Its f_T is measured at I_C = 4 mA, V_CE = 10 V, and f = 100 MHz, confirming suitability for narrowband VHF amplifiers and local oscillator buffer stages.

The 3.0 pF output capacitance (C_obo) at V_CB = 0 V and 1.7 pF at V_CB = 10 V enables predictable impedance matching in tuned collector circuits. Noise figure of 6.0 dB is specified at V_CE = 6 V, I_C = 1 mA, f = 60 MHz, and R_G = 400 Ω - critical for receiver front-end design.

Key Specifications

Pinout & Package

SOT323 package: 3-pin surface-mount plastic case with gull-wing leads, 1.3 mm × 2.1 mm footprint, 0.95 mm height, and JEDEC MO-203-AB compliant outline.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar NPN RF transistor applications.

Compared with MMBT918, ZUMT918TA offers superior thermal performance in same-die RF operation; versus BC817-40, it delivers verified VHF gain and noise metrics essential for receiver front-ends and oscillator buffers.

Availability

ZUMT918TA is available at Aetrix Electronics and suitable for FM radio tuners, UHF remote controls, VHF oscillator buffers, and portable two-way radio driver stages requiring stable component supply across production lifecycles.

Supply support for ZUMT918TA includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design centers across Asia and manufacturing in China, Taiwan, and the US.

ZUMT918TA belongs to Diodes' RF transistor product line, engineered specifically for high-frequency amplification and oscillation in consumer and industrial wireless devices operating below 1 GHz.

FAQ

What is the maximum continuous collector current for ZUMT918TA?

The absolute maximum continuous collector current is 100 mA at T_amb = 25°C. Derating is required above 25°C ambient; at 100°C, maximum I_C drops to approximately 60 mA based on the 330 mW power limit and thermal resistance of the SOT323 package.

Can ZUMT918TA be used in a common-base configuration?

Yes - its V_CBO = 30 V and f_T = 600 MHz support common-base use in broadband RF amplifiers. Input impedance is low (~50 Ω), and isolation between input and output is inherently high, making it suitable for cascode stages where VHF stability is critical.

Is SPICE model data available for ZUMT918TA?

Yes - Diodes Incorporated provides verified SPICE parameter data upon request for ZUMT918TA, including Ebers-Moll and Gummel-Poon model parameters extracted from measured S-parameters and DC curves, supporting accurate AC and transient simulation in RF design tools.

How does ZUMT918TA's noise figure compare at different frequencies?

The datasheet specifies 6.0 dB at 60 MHz with R_G = 400 Ω. While not characterized across full band, typical trend shows NF increases to ~8–9 dB at 200 MHz and ~12 dB at 433 MHz due to base resistance and parasitic effects - consistent with other SOT323 NPN RF transistors of this class.